New document file formats explained

Data integrity
The differences between Open Document and Microsoft’s Open XML begin at the file component level: Open Document places all the content, text, headers and footnotes into one file.

Microsoft’s Open XML also takes this data from the main XML file, which Word 2007 saves in the DocX container using the name Document.XML.

The DocX file will also contain, for example, Header.XML, Footnotes.XML and Endnotes.XML. However, these only contain the footnote or header definitions.

From a user’s point of view, the differences between the formats can have other consequences.

In defective or only partially loaded new-generation files, embedded pictures can go missing, without the text content being damaged. This makes it easier to recover data from partially corrupt files.

Microsoft’s Open XML, thanks to its even stricter division between content and format, has an advantage over Open Document in this respect.

In Open Document, format definitions are stored together and storage space is used more sparingly than with Open XML. On average, Open XML files are two-to-three times larger than their Open Document equivalents.

The software manufacturers are moving in different ways to implement the competing file formats in their office suites.

The Open Document faction – consisting of the Openoffice.org developers as well as Koffice, Sun, Novell, Oracle and IBM – uses the Odt file type by default, while still allowing conversion to previous formats and alteration of the default settings.

Writer, part of Openoffice.org, saves as Odt not Doc. The same principle goes for Office 2007 and Open XML: XML is the default format, but in compatibility mode Word, Excel and Powerpoint read and save the existing binary format files.

To allow users of older Microsoft programs to open Open XML files, conversion tools are supposed to be released at the same time as Office 2007. Users of Office 2000, XP and 2003 will then be able to read and write Open XML documents.

Although Microsoft promises to make the Open XML definitions available without charge, the format differs in this aspect from Open Document. Its requirements are already public and developers can integrate them in their own products.

The standards body Oasis (Organisation for the Advancement of Structured Information Standards) does not levy any licence fee for this.

Free tools for Open Documents
The availability of the Open Document standard is also bearing fruit in other areas, and tools have been developed that show the potential of future applications.

An Open Document Converter (AODC) converts Open Document files into HTML pages. ODF Reader displays Open Document text in a Firefox 1.5 browser window.

Still under development is the Open Open Office (O3) Plugin, which will allow Microsoft Office users to work on Open Document files.

Even if it looks as if there will be a format war between Open Document and Open XML, users will be the winners, as the common basis of the file types – XML – will mean more cross-application compatibility and portability when using office documents.

Further information
Definition of the Open Document standard
www.oasis-open.org/specs/index.php#opendocumentv1.0

Open XML Formats Developer Group
http://openxmldeveloper.org

Microsoft Open XML Translator project
http://sourceforge.net/projects/odf-converter